Video engagement analysis with deep learning
One of the key terms in the literature that you are looking for is video captioning.

You can have a look at some of the relevant papers with code on this subject. In short, it is an active area of research and a difficult problem, one reason is because videos are still difficult to learn about (because of larger amount of data + larger model, etc...) and this model has to be working with two modalities of data: text and image.

A paper that you might want to start with is Deep Visual-Semantic Alignments for Generating Image Descriptions which works on single images. In short, you can use something similar like in the paper: object detector (e.g. Faster RCNN) to extract visual features and feed them into the state of an RNN (LSTM) which would output a sequence of words in your summary (see picture below).